Cord fabric



Qcto fr v R'. vD. EVANS A l /fl CORD FABRIC f Filed March 13, 1925 RLL LRR

INVENTOR RhySllEvans,

u u u BY ATTORN EY Patented Oct. 23, 1928.

lUNITED lSTATES PATENT OFFICE.

BHYS D. EVANS, OF AKRON, OHIO, ASSIGNOR TO THE GOODYEAR TIRE & RUBBER COMPANY, OIF AKRON, OHIO, A CORPORATION OF OHIO.

com) FABRIC.

Application led March 13, 1925. Serial No. 15,233.

wear resulting from repeated ilexure under' tension.

y tion of a cord assembled by properly arrang- Another object of -my invention is to provide a new cord fabric whose cords do not readily fail from internal chafing due to flexure under tension.4 l

Another object of my invention is' to provide a fabric for usein the manufacture of cord tires for vehicles, which shall give better and longer service.

Briefly, the invention consists in disposing the subordinate elements comprising a cord in such manner that the destructive action,l

which results from any intra-cord motion under tension, will be reduced to a minimum. With these and other objects in view, my invention will be more fully described', illustrated in the drawings and particularly pointed out in the appended claims.

In the drawings:

Fig. 1 is an elevational view of a portion of a yarn, utilized to form a cord in accordance with my invention;

Fig. 2 is an elevational view of a. portion of a strand, formed of a plurality of yarns, such as shown in Fig. 1;

Fig. 3 is also an elevational view of a poring a number of thestructural elements shown in the previous figures;

Fig. 4 is a diagrammatic View of a fabric construction embodying my cord in which the cords are singly alternated between those having their last two twists to the right and those having their last two twists to the left;

and

. Fig. 5 is a diagrammatic view of a fabric construction embodying my cord in which groups of cords are alternated between those having the last two twists to the right and those having their last two twists to the left.

In setting forth the details 0f my inven-l tion, I shall describe a cordv having three nrogressively subordinate elements. It should he understood, however, that the principles are not limitedto this particular construction, but may be applied to others without de parting from the scope of the invention. It is customary to designate thevthree elements which comprise the oord as ber, yarn and strand. This will be better understood by referring the drawings. A yarn 1 is formed of spun textile fibers 2, a plurality of yarns being twisted together to make a strand 3 and, finally, a plurality of strands are twisted together to form a cable or cord 4:.

A common characteristic of all previous cordfconstructions for tires lies in the fact that the last two twists (in the example shown this would correspond to twists of the strand and the cable) A'are in opposite directions. The number of turns per inch in any twist may vary according to the use which is made ofthe product, but the directions thereofI have long been fixed. i

It is obvious that with such. a cord, i. e., one having three subordinate elements, four possible constructions lie within the scope of present day practice. l

If such a cord is twisted and ythenl released,

it will tend to regain its former state of equilibrium. The reason for this phenomenon lies in the fact that the various elements comprising the cord are twisted in opposite directions and the forces tending to relieve their stressesoppose each other. In a well constructed cord the opposing stresses are so matched that there is no net effect, this resulting in what is known as a balanced cord.- The property dealing with the inherent tendency toestablish an equilibrium between the opposing stresses is known as'the cord-balance. If an equilibrium has not been reached, the cord will tend to curl and kink and is said to have a poor cord-balance.

I have discovered that cords having their last two twists in opposite directions possess the following characteristic. The yarns near the center of the cord'and at the periphery of a strandlie at a large angle with respect tothe axis of the cord. In cords, such as have been used in the construction of pneumatic tires, this angle approaches so that these yarns near the center of the cord lie substantially transverse to the direction of the cords axis.

When such cords are subjected to tension and flexure the stresses developed react destructively inasmuch as any relative motion between yarns of adjoining strands will effeet a chafing action attheir point of contact. This action is severe because such contacting yarns of adjoining strands near the center of the cord rub against one another in a direction substantially transverse with respect to the axes of the yarns themselves.

I have discovered that it is possible to secure a satisfactory degree of cord balance by making the last two twists in the same direction, and by so doing to secure a very much greater resistance to internal chaiing under tension than is realized with cords whose last two twists are in opposed directions.

Thus, by making the strand and cable twistsv in the same direction, as illustrated by the arrows 5 and 6, I have produced a marked change in the inherent characteristics of the cord structure. The yarns 8, at

ythe periphery of a strand and nea-r the center of the cord are substantially parallel to Ithe axis of the cord. This change obviates the former failing because the yarns in adjoining strands are now substantially parallel to `each other wherever they are in engagement, and any rela-tive motion within the cord is parallel to the direction of the yarns. It is obvious, therefore, that chafng and cutting under tension is reduced to a minimum.

In a number of test runs .I have compared the behavior of cords constructed b prior methods with mine. Such tests establish that the cord of my invention will withstand ten.

Direction o! twist Yarn Strand Cable 1 Right Left Left, 2 Lett.` Right Right.

Those skilled in the art will appreciate that, in so radical a departure from the established fundamentals of cord construction, special precautions are necessary to elect a good cord-balance. In the new construction it is much more diiiicult to establish a static equilibrium between the opposing forces but, bearing in mind that a good cord balance is merely a convenience and not a property upon which the strength, durability or elasticity depend, I have found several procedures conveniently. applicable* to offset `its solution or dispersion of the stiil'enmg mar y terial and subsequentl dried.

Another method w ich may.' be employed lto effect the same result is to dispose the in- A dividnal cords in such manner that their unbalanced forces will oppose' each other. This may better be understood by referring to Figs. 4 and 5 of the drawings'. 1 If we assume that a cord in which the lasttwo twists are to the right will tend to curlto theleft and one in which the last two twists are to the left will tend to curl to the right, it'is obvious that, by alternatino'lthe,y construction of the individual cords, their relative tendencies to curl will offset each other. Fig. 4-

illustrates this arrangement where` the cords v are singly alternated. Likewise, groups of cordsmay be alternated to effect the same result, as illustrated in Fig. 5.

The thirdmethpd of obviating the i ifects of an unbalanced cord is to proportie the degree of twist in each element so that` the internal forces substantially neutralize each other. This necessitates an entire readjustment of specifications used in the present standard practice, not only in the relativey wi l direction of the twist, but also the degree..v thereof. For example, the following table compares the changes in the degree of twist which are necessary in order to obtain a balanced cord without seriously interfering with the properties which enhance its durability.

Newrwis: ordinaryewxst l Degree Directi D Dmn- :ums/inch tum/inch Yam mgm' 20:02am- Righc laste 17.5 strana me amm,..- Right 1s w11 Cable Itt. M010,.-- Left 7 to 8 This table applies to a' specific cord known in the art as 23s/5/8, that is, three strands have been twisted to form the cable; five yarns have been twisted to form each strand; and the yarn employed is of the size known as 23s in the'cotton-spinning industry, that is, twenty-three` 840 yard-lengths will weigh one pound.

From the description given, it appears that the value of my'invention lies in the fact that .where there is relative mot-ion within the cord, the direction of the peripheral yarns ibs iis

elements utilized or the' de ee of twist thereof. It is obvious that-a fa ric embodying this cord constructionv is ,especiall adapt` ed to vehicle- 'tire'manufacture a.l owever,

its applicability is ynot limited to this eld to ot er of/the prmciples of'my invention alone but may be advantageously extended roducts in which durability and undiminis ing strength are -of aramount importance, as for` example. vbelt1ng, pa1clk ing, etc.

Although I have described the a l plication diy utiliz-V mg a specific cord composed of three-progressively subordinate elements (23s/5/3), it is evident that it is not so limited and that many modifications ma be made in the ap' plication ofthe princip es which I have herem setforth' without departing from the s irit of the invention. l I desire, therefore,

at it shall be limited only in accordance with prior art-and the appended claims.

What I claim is:

1.- AV cord comprising a plurality -of strands, each strand Vbeing composed -of a plurality of yarns, theylarns at the periphery cord.-

- element bein D 'subordinate e ments twisted together in the of the strands near e center of the cord Y being substantially parallel to ,the axis of the 2. A cord structure -comprising a cable composed of a plurality of elements twisted together in` a predetermined direction ea'ch composed of a plurality oi same direction as the first mentionedkclelio ments.

3. A cord structure comprising a plurality of strands each composed of elements twisted together, said elements -at the periphery of an strand near the center of the'cord bein sugstantially parallel to the cords axis an the sizeof 'the yarn, the number of twisttwist anda yarn twist, the cable and strand` 4 twists bein 1n the same direction.

5. A cor fabric comprisin a plurality of cordseach composed of twiste strands forming a cable, a pluralit of the cords having their strands and .cab es twisted in one directionand a plurali of the cords-having their strands andcab es twisted in the opposite direction.

6. vA method of manufacturing a cord that one ection to form a yarn, twisting alplurality of yarns in a reverse direction to form a strand and twisting -a plurality of such strands in the last; named direction to form the cord. Y

y 7. A method of manufacturing a cord that comprises twisting a plurality o twisted` elements in one direction to form a strand and twisting4 a plurality .of such strands in Lthe same direction to form the cord.

8. A fabric for pneumatic tires embod ing a plurality' of cords, each having t ree twists, alternate cords of the fabric having their` last two .twists in one direction opposite the direction of the first twist.

comllses spinning a plurality of fibers in 9. A cord fabric comprising a plurality* of groups of cords, each cord of one group mc u acable twist and a-strand twist both in one direction, each cord of the adjacent group including 'three or moreelements and having a cable twist and a strand twistboth in one direction opposite the first mentioned direction.

my name- A In whereof, I have hereunto signed 76' ding three ormore' elements and having, 

